Cushion cap



F. L. GILLEN CUSHION GAP April 7, 1931.

Filed May 24, 3929 Patented Apr. 7, 1931 UNITED STATES FRANK L. GILLEN, OF FLUSHING, NEW YORK cUsnroN CAP Application filed May 24, 1929. Serial 110.365,644;

This invention relates to devices for eliminating water hammer from piping systems. One object of the invention is to provide a device. of the character described having improved cushioning means to eliminate water hammer from a p-iping system, which meansA shall be permanent and efficient in action, and yet simple in construction.

Another object of the invention is. the prolo` vision of a` device of the. nature set forth having air as a cushioning medium, and improved means to avoid loss of the air by dissipation, entrainment by the water, or any other reason.

Another object of the invention is to construct an improved device of the type mentioned having air as: a cushioning medium, and in which the air is retarded or cut od' on the rebound or return of the wave in water A hammer.

A further object of the. invention is to furnish a device. of the character described in which the communicating means between the air cushion and the water is improved in 25. form and construction aswell as in co-operation with the said air cushion to prevent loss of the latter.

Other objects and advantages of the invention will become apparent as the speci- 3o fcation proceeds.

lVith the aforesaid objects in view, the invention consists in the novel combinations and arrangements of parts hereinafter de scribed in their preferred embodiments,

pointed out in the subjoined claims, and illus,-

trated on the annexed drawing, wherein like parts are designated by the same reference characters throughout the` several views.

In the drawingt-n Figure l is a vertical sectional view in closed position of a device embodying the invention.

Fig. 2 1 is a similar fragmentary view of the device, in closed position.

Fig. 3 is; a view in side elevation of an air cushion protecting element and valve.

Fig. 4 is a sidey elevation of a tubular device with which the said element coacts.

. Fig, 5 is a, plan sectional view taken on line 5---5` of Fig. 1,

Fig. 6 is a view in side elevation of; a typical application of theinvention.

The advantages 'of the invention as .herek outlined are best realized when all of its features and instrumentalities are combined in one and the same structure, but, useful de:- vices may be produced embodying less than the whole.

It will be obvious to those skilled in the art to which this. invention appertains, that thesame may be incorporatedin several different constructions. .The accompanying draw-l ing, therefore, is submitted merelyzas showing the preferred exempliiication of the invention. Y c5 Water hammer. occurs whenever a vvalve. or faucet is quickly shut off and causes considerable strainonV the pipes, fittings, and other associated parts, sometimes breakin a connection. Thisis due to the fact that the water flowing at; high velocity through a pipe is suddenly stopped. `They energy of the rapidly flowing water then expends itself in hammering. The pipes and fittings. give slightly', and at' any: rate, the velocity wave is reversed, and keeps rebounding back and forth until the energy represented by the velocity of the water, has spent itself. The force` of the hammering vibrations is extremely high, and the waves act very rapidly.` S0 Under the circumstances, the air cushion that is usually employed isi dissipated by absorption at high pressure by the. water, or entrainment due. to the velocity of the water, particularly on the reverse or return of the c5 water. By this invention the loss of the air cushion is prevented, so that the device may have the longest possible life.

Water hammer may occur in piping sys-- tems even whenv it is not heard, but the jars and strains will be present, unless the system is properly cushioned. Thus there may be present the forces to break or loosen any weak partsV of the system,such, for example, as theV valves, washers, and the like. 95

Generally described, the invention provides an air cushion having restricted communication with thewater by any suitable means, only one. of which is herein shown, including a tubular member extendingv upward into the air cushion, and affording a reduced area of communication therewith. Coacting means may serve to retard the response of the air cushion on the reverse or return of the pressure wave, and this may constitute the tubular member itself or a rigid or movable member as may be found most desirable. lf the latter, a valve may co-operate which opens automatically to permit the air cushion to function, and closes instantly that the pressure wave recedes. The air cushion is thus prevented from being drawn or sucked out by the reversed pressure wave. This result has always dissipated the air cushions in devices of the prior art even though the air cushions diminish the hammering action of the water. The said valve is preferably of hollow form toreceive the upper end of the tubular member. The annular wall or flange of the valve may act as a defiector for any water that may surge upward through the tubular member into the air cushion to prevent loss of air by the spray of the water. It has been found desirable to extend the said annular wall of the valve into proximity to the bottom of the air cushion chamber, thereby mo-re eectively trapping the air.

The invention may be made up in various forms only one of which is shown. In the form disclosed, it comprises a pressure cap, into which the air cushion protecting means are easily inserted, the entire device being simple and inexpensive to manufacture, foolproof in operation and particularly adapted for quantity production. I

Referring in detail to the drawing, 7 denotes a device embodying the invention. The same includes a. cushion cap 8 comprising a pipe 9 closed at its upper end by a member 10. The cushion cap 8 may also be made with the pipe and closure 10 of integral construction. rlhe cushion cap is connected with a water pipe 11 by a. T 12 and a reducing coupling 13. A fiush valve 14 or the like is connected to the T.

The device 7 is thus in the nature of a cap, although it will be understood that it can also be made in other ways, as will be clearly apparent. It has an internal pipe thread 15 about half its length. At its lower end is an external thread 16 for engaging the coupling 13.

Disposed within the cap are alined tubular members 17' and 17a which are open throughout. An end of each is threaded at 18 as shown, and the upper tubular member 17 has a suitable smooth valve seat 19. The said tubes are of smaller diameter than the cushion cap 8 to provide an annular space therebetween.

A bushing 20 has a central hole 21 that is threaded for screw engagement with the members 17 and 17a at the threads 18. It has also an external thread for engaging the thread 15 of the cap. The two tubular members are jammed and tightened against each other and with the bushing 20.

Coacting with the tubular member 17 at the seat 19 thereof is a valve 22 which may assume various forms within the scope of the invention. lt can be made of various rustless materials either composition or metal, and among` the latter may be mentioned the soft `metals such as lead. The purpose of the latter is to render the valve adapted to seat in a fiuid tight manner regardless of any irregularities in the seat. l/Vhile the valve might be made of a disc form, it is preferred to use a hollow valve, the same comprising a valve portion 23 and a cylindrical wall 24. The hollow valve receives therein the tubular member 17. The valve portion 23 may be slightly thicker than the wall 24, and it acts as a closure for the upper end of the annular wall 2li. rThe latter acts as a detiector as will be more particularly described hereinafter, and while it might be used independently of the valve portion 23, certain improved results follow from the unitary association herein described.

The hollow valve extends with the end of its wall 24 in proximity to the bottom of the air cushion chamber, at the bushing 20. It is gravitationally self closing, although any auxiliary means in the nature of a spring could be used. The wall 24 serves also as a guide for the valve 23. To assure fluid tight engagement between the valve 23 and the tubular member 17, the valve may be made of lead, or other soft metal. |The valve is opened by the action of water hammer thereon, and the cap 23 may act to limit the opening movement referred to.

The invention is not to be restricted to any particular kind of valve, since it can be practised with valves of various types, and since it can be readily modified to adapt it to cooperate with any valve, and whether gravitationally or spring actuated.

In Fig. 2, the tubular air cushion protecting means is shown as a unit, thus emphasizing the simple construction of the invention. On placing the valve 22 on the tubular member 17 the latter is passed upward into the cushion cap 8 and the bushing 20 screwed home. Since the tubular member projects beyond the open end of the cushion cap, sufiicient grip is afforded by means of any suitable 'tool for turning the bushing as stated. By the use of a suitable gage to measure the length of the projecting end of the member 17a, the position of the valve 22 with reference to the member 10 is accurately determined, to limit the opening movement of the valve.

In operation, a pressure wave in water hammer acts through the member 17 to lift the valve 22. The air cushion in chamber 26 is then available to eliminate the hammer.

As the wave recedes, the valve closes and prevents air from being entrained or sucked out by the water.

The tubular members 17 and 17a serve to provide an air cushion space, together with the space 26, within the cushion cap. When a pressure wave recedes, a powerful closing action is exerted on the valve due to suction. Thus the pressure built up in the space 26 is retained therein, and loss of air is avoided by entrainment by the water in the tubular member 17 and elsewhere. When the pressure waves in water have fully subsided, the excess pressure will gradually leak out and become equalized.

A small quantity of water 27 will surge through the member 17 and into the air cushion chamber at the crest of the pressure wave vi'n water hammer. This water is deflected directly downward by the wall 24 and cannot act as a spray, the particles of which would seize upon the air and cause a loss thereof.

The water 27 may act in the nature of a seal to avoid loss of the air that constitutes the air cushion.

The tubular members 17 and 17 a being of relatively small area in cross section, tend to slightly throttle the surge in water hammer and avoid excessive mixing between the air and the water, and so cause the air in the said tubular members to remain there for a maximum period of time.

It will thus be seen that I have provided a device which fulfills the several objects of the invention and is well adapted to meet the conditions of practical use.

I claim 1. A device of the character described, including an elongated cap internally threaded, and closed at its upper end and adapted to be connected with a water pipe at its lower end, a bushing screwed into the cap to lie therein between the ends of the cap, a tubular member threaded to engage in the bushing, a valve seated on the upper end of the tubular member and enclosing the same, the upper end of the cap being a stop for the valve, the space within the cap above the bushing being an air cushion chamber, the valve being of such weight and compactness as to be opened by a pressure wave but closing as the pressure wave reverses.

2. A device as set forth in claim 1 in which said hollow valve includes an annular wall that extends into proximity to the bottom of the air cushion chamber.

3. A device as set forth in claim 1,

FRANK L. GILLEN.

wherein said hollow valve is made of a soft metal, for the purpose set forth.

4. A device of the character described, including a water pipe, a valve therein, an air cushion chamber to eliminate water hammer on the sudden closing of the valve, a tube coacting with the chamber and extending there- 

